Guan Yun has guarded Dragon Lake for three years, all to catch the legendary hundred-year-old black carp king. Unable to endure their poverty, his fiancée, Su Wan, breaks off their engagement after being egged on by her best friend and marries rich second-generation heir Liu Zhihao instead. The entire village mocks Guan Yun as the "Air Force Commander" for never catching anything, but he trains tirelessly in fishing under the guidance of an elderly man. At the Fishing King Cup, he uses a broken fishing rod to overcome three consecutive challenges, eventually catching a 98-jin black carp king and winning the championship. Liu Zhihao goes bankrupt, his best friend loses her influence, and his ex-fiancée is consumed with regret. Guan Yun not only wins a million-yuan prize but also wins the genuine affection of Lin Xi, the daughter of the richest man. The Song Dynasty treasury coin found inside the black carp king's mouth unveils Dragon Lake's thousand-year-old secret.